1、 Project Overview 
Project Name: Wuhan Country Garden Phase II Yangtai Flat Plate Solar Hot Water Project This project is located in Wuhan, Hubei Province; The total number of users is 308, consisting of 11 buildings with a total construction area of 120500 square meters, including 6 small high-rise buildings and 5 high-rise buildings.  
Project location: Qinhuai River Road, Yantai Development Zone, Yantai City, Shandong Province 
Feasibility analysis of installing a natural circulation solar hot water system The principle of a natural circulation solar hot water system is to use the thermosiphon effect. The flat plate collector absorbs the energy irradiated by the sun and converts it into heat energy, which is transferred to the medium (heat medium) inside the collector. As the temperature of the medium increases, its density decreases, forming natural convection with the medium inside the water tank jacket, causing the temperature of the medium inside the water tank to rise. Then, the energy is transferred to the water inside the water tank, causing the water temperature inside the water tank to rise. When the solar radiation cannot meet the design conditions in rainy weather, the thermostat will control the built-in electric heating system of the water tank to provide auxiliary heating to meet the user's water needs. 
The cyclic conditions derived from the cyclic principle are: 

(1) The installation position of the water tank should be at least 30mm higher than the collector to facilitate circulation.  
(2) The circulation pipeline should always maintain an upward slope and there should be no reverse slope in the middle.  
(3) The distance between the water tank and the collector cannot exceed 3.5 meters. From the installation conditions provided in this project, it can be seen that they all meet the circulation requirements, so it is feasible to install a natural circulation solar water heater in this project. It should be noted that the water tank of the solar hot water system for Unit A in Building 41 needs to be installed outdoors. Due to the influence of the roof water collection pipe arranged on the south side of the bedroom in Unit A, the water tank is designed to be located at the junction of Unit A and Unit B. In order to not affect the overall appearance and effectively protect the water tank from rain, sun, etc., it is recommended that Party A install a waterproof grid on the outside of the water tank location.  
2. The design principles and objectives are to meet the daily hot water supply needs of residents in the community, reflect the maximization of solar energy utilization, the maximization of hot water utilization, and the minimization of operating costs. Based on the actual requirements of Party A, we propose the following design principles and objectives 
Goal: 
(1) Provide household hot water supply for residents in the community, ensuring an average daily hot water temperature of 60 ± 5 ℃ throughout the year.  
(2) The installation of solar hot water systems should not only ensure the daily hot water supply for each household, but also ensure that the sunlight standard of adjacent buildings is not reduced, and the overall style of the building facade is not damaged. 
(3) The installation of solar collectors should meet the requirements of building load and wind resistance, and should not cause light pollution to the surrounding environment after installation. 
2、 Design and Construction Instructions 1. Design Basis 
(1) GB/T18713-2002 Technical Specification for Design, Installation and Engineering Acceptance of Solar Hot Water Systems 
(2) GB50015-2003 "Code for Design of Building Water Supply and Drainage" 
(3) GB50364-2005 "Technical Specification for Application of Solar Hot Water Systems in Civil Buildings" 
(4) GB/T6424-2007 Flat Plate Solar Collectors 
(5) GB/T19141-2003 Technical Conditions for Household Solar Water Heaters 
(6) GB4272-92 "General Principles for Thermal Insulation Technology of Equipment and Pipelines" 
(7) GB50009-2001 Load Code for Building Structures 
2. Design parameters 
We have finally determined the design water supply temperature to be 60 ℃ based on the requirements, design principles, and objectives of Party A. The water supply is 5080L per person per day. Taking the average, the maximum daily water supply per person is 60L, and the average daily hot water supply per person is 30L. 
A. Configuration Design of Solar Hot Water System 
(1) The water tank is designed for an average of 2.6 people per household, with a capacity of 80L. Specifications: external dimensions ф 480mm × 840mm, empty box weight: 42kg. The water tank has the following technical advantages: 
The water tank is an enamel pressure type water tank, with a vertical jacket inside. The heating method is to use antifreeze medium for heat exchange, with a jacket heat exchange area of 0.6 square meters and a heat exchange efficiency of 91-95%, meeting relevant industry standards. The outlet pressure is provided by tap water, which is stable and does not require manual water filling; The shell adopts galvanized sheet spray coating surface treatment, with a wall thickness of 0.5mm, uniform color, and strong corrosion resistance and oxidation resistance of the coating; Will not cause light pollution to the surrounding environment; Polyurethane high-pressure foaming, with a molded density of ≥ 48kg/m. The thickness of the insulation layer is 45mm 
Baosteel produced SPCC special enamel steel plate for inner liner, material BTC-340R, wall thickness δ 2.0; 
High end enamel material, imported from Fulu Company in the United States, with high temperature resistance, no pollution, toughness, and enamel thickness of 0.2mm 
Fully automatic welding solves the problem of uneven welding. The production process adopts German automatic spray coating and rolling coating technology, and uses two enamel coating techniques to form two layers of special protective glaze. The surface glaze can prevent oil stains, and the bottom glaze can prevent rust;  
Strong ability to withstand sudden changes in high temperature, with a temperature range of -60 ℃ to 450 ℃;  
Acid resistant, alkali resistant, high temperature resistant, all kinds of ions cannot penetrate its surface, effectively ensuring clean water quality. 
(2) Collector 
The calculation of heat collection area in this system is an indirect circulation system, and the following formula is used for calculation: 
Firstly, the collection area of the direct system should be calculated: according to the specifications of the Megaray flat plate collector, we take the total area of the flat plate collector as 2.0 square meters, the external dimensions as 2000mm × 1000mm × 80mm, and the weight as 27kg. Characteristics of the collector: The working process of the flat plate collector is that sunlight passes through the glass cover plate and shines on the coated heat absorbing plate on the surface. After the heat absorbing plate absorbs solar radiation energy, the temperature rises. Requirement: Has a certain pressure bearing capacity, good compatibility with water, good thermal performance, that is, the heat converted by the heat absorbing plate after absorbing solar radiation can be quickly transferred to the water. The size of the flat panel solar collector commonly used for a balcony is 1m × 2m or 2.5m × 0.8m (can also be specially customized), and under design conditions, it can generate about 70-130 kilograms of hot water at 45-65 ° C per square meter of lighting area. Cover plate: Made of 3.2mm ultra white low iron cloth grain tempered glass, the internal ripple treatment of the glass has the effect of frosted glass blocking the line of sight. Even under strong sunlight conditions, it will not cause light pollution due to refraction and reflection caused by sunlight exposure. The iron content of glass is less than 80ppm, and the extremely low iron content ensures the transmittance of the cover plate. The visible light transmittance is as high as 92%, the sunlight transmittance is as high as 91.5%, and the emissivity is only 3-5%; Anti hail and anti-aging. The distance between the cover plate and the heat absorbing plate is about 25mm. Core: The flat plate solar collector adopts the leading domestic fully automatic laser whole plate welding technology, with good forming quality, low thermal resistance, minimal damage to the surface coating of the heat absorbing plate, and more beautiful appearance; Advanced copper tube punching and flanging technology makes the flow channel more reliable after welding. Coating: The board core is coated with German Tinox magnetron sputtered blue titanium coating, which has a thermal absorption rate of ≥ 95% ± 2 and an emissivity of ≤ 5% ± 2. It is currently the most efficient solar heat absorbing coating in the world. Shell: The frame adopts an integral bite structure design, thickened aluminum alloy, ensuring a product service life of over 30 years. At the same time, there is a dedicated windproof connector slot to ensure higher outdoor fixing strength and more beautiful appearance. The back plate of the collector is mechanically pressed together to ensure no leakage during product use and improve the overall strength of the collector, thereby ensuring safe use. (3) The auxiliary electric heating water tank is equipped with electric auxiliary heating. When encountering rainy weather, electric auxiliary heating can be used, which can be used for both light and electricity. According to the installation position of the electric heating tube and the principle of water stratification, the required heat for heating is Q=CM (Tend tL)=4.2 × 80/2 × 50=8400KJ. The design can heat to the desired temperature in 100 minutes, and the thermal efficiency of the water heating equipment is calculated at 95%. The power of electric auxiliary heating is P=W/(T × η)=1474W, and the actual power of electric auxiliary heating in the area is 1500W. 
(4) Intelligent control instrument 
The intelligent control instrument mainly has the following functions: 
The display panel of the intelligent control instrument displays the water temperature in the water tank in real time through the water temperature probe; 
● It can be heated at a fixed temperature and time, and when it reaches the predetermined temperature, the electric auxiliary heating will be automatically turned off; 
● Constant temperature heating can be set. When the temperature is lower than the set temperature, electric heating will be automatically turned on, and when the set temperature is reached, electric heating will be automatically turned off; 
● Leakage protection function, automatically shuts off when the auxiliary electric heating leaks electricity; 
(5) The safety relief device is equipped with a safety relief valve at the inlet of the water tank to maintain a constant pressure inside the tank and ensure safe use. If the pressure inside the water tank is too high, the pressure relief valve will automatically release the pressure, and water will flow out from the pressure relief port to protect the water tank. 
(6) Magnesium rod has anti-corrosion function, protecting the inner tank of the water tank from corrosion. 
(7) The circulation pipes of the pipeline fittings and insulation system are connected with copper pipes, which transfer heat more quickly. The pipes are heat-resistant at 110 ℃ and pressure resistant at 1MPa. All pipeline connectors are made of brass. The insulation of the circulation pipeline is made of polyethylene material and wrapped with wrapping tape on the outside. 
(8) Thermal conductive medium 
The thermal medium of the system has functions of antifreeze, anti-corrosion, and rust prevention. Based on the historical lowest temperature in different regions, our company provides thermal conductive media with different condensation temperatures. In the Yantai region, we provide thermal conductive media with a condensation temperature of -25 ℃. 
B. The circulation principle of solar hot water system: The balcony style solar hot water system adopts natural circulation for heat collection and exchange. This type of heat collection method requires the water tank to be higher than the collector. Sunlight shines on the flat plate collector, and the core of the collector absorbs heat, heating the heat transfer medium of the copper tube in the collector. The temperature of the heat transfer medium in the collector increases while its density decreases, forming convection with the denser cold medium in the water tank heat exchanger due to gravity. This cycle repeats, heating the water in the water tank. 2) Instructions for fixing the water tank: ① Horizontal water tank ② Vertical water tank: The thermal storage water tank is treated separately according to the load-bearing capacity of the wall.  
Method 1: Reinforced concrete and load-bearing concrete blocks (core injection) and other walls are fixed with expansion screws M10 × 110; 
Method 2: For lightweight partition walls and masonry with a wall thickness less than 120mm, fix them with M16 or above through wall bolts; 
Method 3: Non load bearing blocks such as aerated concrete are fixed with expansion screws M10 × 110 and supported with brackets to support the water tank of the water heater.  
6. Construction organization design 
Construction phase division and control points: 
According to the characteristics of the project, the construction period can be roughly divided into the following stages: 
Phase 1: Construction preparation (material procurement, equipment production, transportation, design and construction drawing, on-site investigation);  
Phase 2: Installation of reserved equipment components (pre embedded installation of fixed components for solar hot water systems); 
Phase 3: Installation of equipment system (installation of solar hot water system); Phase 4: System operation and debugging.  
The main control points are as follows: 
Construction preparation stage: Before installation, inspect the site to see if it has the construction conditions for installing a solar hot water system. Confirm the feasibility of designing reserved fixed parts based on the actual situation on site. After confirmation by relevant professionals, arrange for the procurement of materials and materials, production of collectors, and processing and manufacturing of embedded parts. Installation stage of equipment reserved parts: Before installation, confirm whether the site has the construction conditions for installing the solar hot water system. Based on the actual situation on site, confirm the feasibility of designing reserved fixed parts. After confirmation by relevant professionals, the civil construction team will reserve the equipment. Equipment installation stage: Strictly follow the current national construction acceptance standards and regulations, and achieve a targeted and step-by-step approach. Consider comprehensively during the construction process. When installing pipelines, valves, and brackets, the aesthetics of the brackets should be ensured. System operation and debugging phase: Ensure that the system can be used normally and guarantee the quality of the project.